GEORGE BUSH has made it official -- more or less. The vice president is now "exploring" the possibility of running for president. He is setting up an "exploratory committee" to do that and to work in his behalf. It will raise money from Bush backers and spend it on efforts it hopes will produce Bush delegates at the 1988 Republican National Convention.

You might well ask: so what else is new? Everyone knows Mr. Bush is running for president, and those who scan political reports carefully know that he and two other Republicans -- Jack Kemp and Pat Robertson -- have been running candidates in the precinct delegate contests this summer that will determine the makeup of Michigan's Republican delegation in 1988.

Mr. Bush could have used his announcement as an occasion for publicity. Instead it was made late on a Friday afternoon. We see two reasons for that. First, Mr. Bush was abandoning, after taking some flak, the palpably absurd position his lawyers took before the Federal Election Commission: that the Michigan precinct delegate contests have nothing to do with the presidential race. They do, and by setting up an "exploratory committee" that will ultimately be bound by federal disclosure requirements and limitations on contributions and spending, Mr. Bush is acknowledging that he's doing what he's doing. Though belated, it provides a nice contrast with Mr. Robertson, whose cause in Michigan is being championed by a tax-free foundation, and with Mr. Kemp, whose effort there is financed by a Michigan PAC that does not disclose contributions or disbursements.

Second, the creation of the "exploratory committee" suggests that Mr. Bush has decided he must make a greater effort in Michigan than he had anticipated. The new committee can do two things that Mr. Bush's PAC, operating under the fiction that it wasn't working for a presidential candidate, couldn't do. Now the Bush forces can campaign openly for precinct delegate candidates and advertise them as Bush supporters. And Mr. Bush's managers will be able to pour as much as $750,000 into Michigan between now and Aug. 5. Mr. Bush did not do as well as expected when it came to filing precinct delegate candidates last May 27; now he is running, if not scared, then at least awfully hard.

The Michigan Republican Party has forced a ludicrously early contest, and candidates have had problems reconciling their efforts there with a legal scheme designed to regulate campaign finances over a considerably shorter period. Mr. Bush has, late in the day, come up with a better solution than the two others competing heavily there. In the process he has raised the stakes, and increased his own risk, in a contest that comes too soon.